A problem with existing methods of producing effects and textures on the surface of cast liquids, for example concrete, is that the resolution of the resulting product is generally not of a level sufficient for fine detail or complicated designs to be sufficiently clear. Whilst the concrete might be able to produce a good level of resolution, the mould in which the concrete is cast is of poor resolution. Furthermore, the depth of the resulting design on the concrete may be insufficient for the design to be visible from a distance.
One method of casting concrete is to produce a mould from wood or other materials into which concrete is poured to produce a cast product.
A further of producing a surface effect in the concrete is to machine a surface effect in relief into the one of the surfaces of the mould and to pour the concrete into the mould. The resulting concrete product takes on the design of the relief surface effect. However, one limitation of such a process is that the quality and resolution of the surface effect is limited by the tool size and machining process.
Another method of producing a mould is to use an object as a pattern and to pour silicone or similar material over the product to produce a mould onto which concrete is poured. For example, an object with a ‘snakeskin’ surface has silicone poured over it to create a mould. The mould is then filled with concrete, reproducing the surface effects on the original object. However, a disadvantage of such a process is that the surface effect is limited to the size, quality and resolution of the original object.
Photopolymer plates are usually used in the printing industry as relief plates for flexographic printing, especially for printing on packaging. The plates are usually in the form of a flexible polymer sheet which hardens when exposed to light. The photopolymer plate has a mask layer onto which light, often in the form of a laser, is directed to create a negative of the image. The plate is then exposed to light to produce the image in relief on the plate. The areas of the plate that have not been exposed to light and un-hardened and are washed away using a solvent, leaving a flexible printing plate, which is hardened and finished prior to use. Methods of producing finished photopolymer plates are known from the printing industry.
EP0196033 (WOJCIK) discloses a method of making moulds that can be used for casting bronze plates, which involves the use of photopolymer plates. The method comprises forming a design on the photopolymer plates, onto which wax and sand are applied to create a mould, into which bronze is subsequently cast using a lost-wax process. The use of sand and wax makes the process time consuming and labour intensive, and reduces the likelihood of multiple castings appearing the same.
IT1119979B (POLLACK) discloses a method of forming three-dimensional objects using photopolymers but involves the use of a lost-wax process.